MongoHealthIndicator not compliant with Mongo stable API with strict setting

[jorgelc]

MongoHealthIndicator uses isMaster command, which is not part of Mongo's stable API https://www.mongodb.com/docs/v5.0/reference/stable-api-changelog/

If the underlying Mongo connection is configured to use the stable API and strict setting, the health indicator yields an error, as Mongo rejects the isMaster command.

Affected versions: Tested with sprinboot 3.3.0, potentially since 3.0.0

To reproduce it, create a blank springboot project including spring-boot-starter-data-mongodb, spring-boot-starter-web and spring-boot-starter-actuator dependencies. Then, set up both Mongo stable API version and strict to true by creating the following bean:

	@Bean
	public MongoClientSettings mongoClientSettings() {
		return MongoClientSettings.builder()
			.applicationName("testApp")
			.serverApi(ServerApi.builder()
				.strict(true)
				.version(ServerApiVersion.V1)
				.build())
			.build();
	}

For reference, such project has been created here https://github.com/jorgelc/mongo-stable-api-springboot-health, with steps about how to reproduced the error and compare the behaviour with when strict is set to false.

[wilkinsona]

Thank you. I've reproduced the problem.

I think we should switch to the hello command. It's supported in MongoDB 5.0 and later and Mongo 4.x reached end of life in February 2024.

[jorgelc]

Thanks @wilkinsona

We implemented that as a temporary workaround locally and it worked for us, but it would be nice to have that supported out of the box.

[jyemin]

Just FYI, the hello command was backported all the way to MongoDB 3.6, so this should be a safe change even for EOL'd MongoDB releases.

[pkunk]

FYI: This is not compatible with Azure Cosmos MongoDB API:
https://learn.microsoft.com/en-us/azure/cosmos-db/mongodb/feature-support-60#database-commands

[wilkinsona]

Thanks, @pkunk, but I'm not sure there's much we can do about that. I don't see any mention of isMaster in the list of supported database commands either so it's not clear that this would have worked before. I'd recommend raising this with Microsoft to see if they can improve Cosmos' compliance with the MongoDB API.

In the meantime, anyone who's affected can work around the non-compliance by defining their own bean named mongoHealthIndicator or mongoHealthContributor.

[SimonedeGijt]

We have the same @pkunk . Did you already raise this with Microsoft? Would be great if I can follow the progress on this item :)

[pkunk]

We have the same @pkunk . Did you already raise this with Microsoft?

No. We just use custom mongoHealthIndicator bean.

[SimonedeGijt]

I created a post now, would be great if many people can vote on it 😄 : https://feedback.azure.com/d365community/idea/c7b19748-9276-ef11-a4e6-000d3a059eeb

[gahl-levy]

Hey @pkunk @SimonedeGijt @wilkinsona . I'm Gahl from the Cosmos DB Product Team. The hello command is already supported in Cosmos DB for MongoDB vCore and Cosmos DB for MongoDB RU. We're adding it to our docs now. Sorry for the confusion here and thanks for pointing this out!

[wilkinsona]

Good news! Thanks very much, @gahl-levy.

[ashishrky]

@gahl-levy is there any setting to enable hello command for Cosmos DB for MongoDB RU? I am running Spring Boot v3.3.4 application, and its actuator health endpoint is still failing with the error...

        "mongo": {
            "status": "DOWN",
            "details": {
                "error": "org.springframework.dao.InvalidDataAccessApiUsageException: Command failed with error 115 (CommandNotSupported): 'Command hello not supported.' on server xxxxxxx-centralus.mongo.cosmos.azure.com:10255. The full response is {\"ok\": 0.0, \"errmsg\": \"Command hello not supported.\", \"code\": 115, \"codeName\": \"CommandNotSupported\"}"
            }
        },

My spring boot app is running in App Service, and everything is located in Central US data center.

[miguelrq]

@gahl-levy looks like the way actuator does health checks is with
mongoTemplate.executeCommand"{ hello: 1 }"
which cosmosdb doesn't support

Against a mongo shell
db.runCommand({isMaster:1}) //works
db.runCommand({hello:1}) //doesn't work